Published PCT-application WO/SE85/00503 describes a device for transluminal implantation comprising a substantially tubular, radially expandable prosthesis, the device comprising in combination such prosthesis and concentric therewith a flexible probe with means for maintaining said prosthesis in a radially contracted state and for releasing same at the desired location. The said means for maintaining and releasing the prosthesis comprises a hose concentrically surrounding the probe, one end of said hose being connected to the probe and the hose being folded inside itself to form a double-walled section radially surrounding the prosthesis to form a compartment therefor. The prosthesis is releasable by axial relative movement of the ends of the hose.
In preferred embodiment of the device of said PCT-application the hose is leaktight and both ends thereof are tightly connected to the probe. Furthermore, the surface of the probe adjacent to the hose is leaktight between the endconnections of the hose, whereby the hose and the probe form a chamber that can be pressurized using a liquid whereby the liquid reduces the contact pressure between the hose walls of the double-walled section thereby reducing the friction between the outer hose wall and the inner hose wall at axial relative movement between same.
ALthough this known device for transluminal implantation operates in an excellent manner when practically used it has been found in use that the prosthesis compartment after introduction of the prosthesis as a preparation for implantation contains gases, mostly air, that are intrapped in said compartment and within the thread elements of the prosthesis. Such gases may when releasing the prosthesis in for example a blood vessel, cause problems when released into the blood flow.
The invention has for its main purpose to alleviate said problem of gases contained in the prosthesis compartment. For said purpose the device according to the invention is characterized in that the probe has a central axial channel that can be used for supplying a liquid flushing medium at its other end. Flushing can take place without closing said channel at its front end but it can, if desired, be restricted or closed to improve the flushing efficiency. Furthermore, the probe is provided with at least one radial aperture opening into the prosthesis compartment to enable flushing of the prosthesis compartment to remove gase therefrom before implantation.
According to a preferred embodiment of the device of the invention several apertures are arranged in the probe substantially evenly distributed around the probe, and said apertures are preferably located behind the prosthesis as seen in the direction of the transluminal transfer of the device.
The invention also provides for means for eliminating the risk of possible release of gases present between the walls of the hose in its double-walled section in case of rupture of the hose within said section. For this purpose the device according to the invention is characterized by at least one small hole extending through the hose wall at the front end of the double-walled section to enable displacement by flushing of gases present between the walls of the hose in said double-walled section. The size of such hole is selected such that it enables escape of the gases but prevents or substantially reduces passage of the liquid used for pressurization. It is preferred to arrange several such holes at the front end of the double-walled section, and such plurality of holes is advantageously located substantially evenly distributed around the front end of said hose section. Although the size of such hole is dependent on the character of the liquid used for pressurizing chamber formed by the hose and the probe a suitable size lies between about 0.001 and 0.1 mm. When using isotonic saline solution as a pressurizing liquid a preferred diameter of the hole is about 0.05 mm.
For further details regarding the device according to the invention reference is made to the above-identified PCT-application, the full disclosure of which is incorporated herein by reference. The present invention will in the following be further described in the form on non-limiting examples of embodiments thereof, reference being had to the appended drawings.